Earnings Per Share (EPS Components) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Summary of earnings per share
Net income	$ 14,746	$ 12,758	$ 28,129	$ 25,010
Weighted Average Shares (in shares)
BASIC SHARES	23,897,413	22,888,155	23,858,456	22,856,132
EFFECT OF DILUTIVE SECURITIES	94,560	52,144	97,544	49,104
DILUTIVE SHARES	23,991,973	22,940,299	23,956,000	22,905,236
NET INCOME PER SHARE (in dollars per share)
BASIC EPS	$ 0.62	$ 0.56	$ 1.18	$ 1.09
EFFECT OF DILUTIVE SECURITIES	$ (0.01)		$ (0.01)
DILUTIVE EPS	$ 0.61	$ 0.56	$ 1.17	$ 1.09